The present invention relates to the use of an extract from snow algae, especially an extract from Chlamydocapsa sp (snow algae) in cosmetic and/or pharmaceutical products. More particularly, the invention relates to Chlamydocapsa sp. (snow algae) in cosmetic and/or pharmaceutical products employed to guard against extrinsic aging of the skin caused by negative environmental exposure, for instance, UV radiation or air pollution, but also to guard against intrinsic aging of the skin as influenced by aging-specific gene expression levels. The invention relates furthermore to a method for producing extracts from snow algae, suitable for topic applications.
The skin acts as a barrier keeping the body safe from dehydration whilst guarding against harm due to chemical and mechanical environmental exposure. Denoted especially harmful to the skin is the UV radiation of sunlight. The skin, like every other tissue, is subject to aging processes. Aging of the skin is termed either intrinsic or extrinsic. Intrinsic aging is a chronological genetically determinate process whereas extrinsic aging is governed by outer factors, smoking and excessive exposure to the sun being deemed especially harmful. These extrinsic factors result in what is called premature aging of the skin.
Aging of the skin is not just a problem cosmetically. Aged skin goes hand-in-hand with a reduced barrier function and thus diminished protection from environmental exposure. This prompts a fatal progression, accelerating aging of the skin even more.
Aged skin is characterized by a reduction in cell regeneration in the epidermis and a drop in the production of collagen structural proteins in the dermis. The skin becomes less elastic and its water content is reduced.
There already exists a variety of cosmetic and dermatological formulations for the treatment of skin aging, the active ingredient used in the main in dermatological products being retinoic acid, whilst in cosmetic products, use is made of, in addition to UV filters, especially antioxidants such as vitamin C or vitamin E.
Plant, algae or fungous extracts rich in natural antioxidants also already find application as active ingredients in cosmetic formulations. Substances especially promising and attractive in this respect are plants or microorganisms exposed to extreme outdoor conditions, organisms thriving in a desert, polar or hot springs environment counting to be extremophilic because they needed to develop special adaptation techniques for their survival in these extreme habitats.
One special species of extremophils are snow algae which biologically count as cryoflora.
Algae are eukaryotic, plant-like organisms living in water capable of photosynthesis but which do not actually count as plants. Snow algae belong to the green algae, they being classified systematically as Chlorophyceae, Division Chlorophyta.
These are microscopic fresh water algae found in the eternal snow and glacier surfaces of polar and alpine regions of the earth (Arctic, Antarctic, Alaska, Greenland, West and East Coast of North America, Himalaya, Japan, New Guinea, Europe, Switzerland, China, Patagonias, Chile and South Orkney Islands). Their natural habitat is governed by extremely low temperatures, high UV radiation and nutrient deficiency to which they have become optimally adapted. They live in a unique microhabitat, namely the free water between the crystals in the snow. They color the massive snow surfaces in polar and alpine regions green and a brilliant red (blood snow e.g. Chlamydomonas nivalis) attributed to the spores of the algae. This red coloration of the spores serves as a UV screen achieved by the inclusion of carotenoids (astaxanthin).
At this time roughly 350 strains of snow algae are known, the most common being Chlamydomonos nivalis. Classifying snow algae phylogenetically is difficult, their systematics being in constant change. Many of the 350 strains stem from wild collections and characterizing algae taxonomically is still anything but complete genetically. The largest collection of snow algae (CCCryo, Culuture Collection of Cyrophilic Algae) is to be found in the Fraunhofer Institute for Biomedical Engineering (IMBT) in Berlin.
Also from an ecological point of view snow algae are becoming increasingly of interest by being able to absorb atmospheric CO2 in thus influencing the greenhouse effect. They also serve as bioindicators, for example, for UV radiation directly involving a reduction in the ozone layer, or the acid-tolerant strains as indicators of acid rain.
Snow algae are collected generally in polar regions, cultivated and taxonomically determined as to the DNA level—see a German paper by Leya T, (2004): “Feldstudien and genetische Untersuchungen zur Kyrophilie der Schneealgen Norwestspitzbergens” concerning testing the cyrophilic reponse of snow algae in the northwest region of Spitzbergen, as published by Shaker Verlag, Aachen. Snow algae nowadays can be durably cultured in corresponding reactors, the temperature management of which together with the correct supply of air and light poses difficulties in culturing. Particularly the temperature requires special attention since growth of snow algae as a cryoflora is an optimum at around 12° C. The normal life-cycle of snow algae begins with germination in Spring when the slow melt of the snow and when sufficient water and nutrients are available. The green algae perform with the aid of chloroplasts photosynthesis and multiply until a relimitation of the nutrients triggers sporulation. Sporulation commences by the algae producing and incorporating carotenoides which protect the spores from UV radiation, resulting in the red algae spores causing the typical red coloration of the snow.
Currently, snow algae research is focussed on isolating various secondary metabolites from the snow algae such as, for example, carotenoides (xanthin, astaxanthin, etc.), cryoactive enzymes/proteins (cryoprotectors, for example) or antioxidants, such as described, for instance, in the paper by Bohne, F. & Linden H (2002): Regulation of cartenoid biosynthesis genes in response to light in Chlamydomonas reinhardtii. Biochim. Biophys. Acta 1579:26-34, Duval B., Shetty K. & Thomas W H (2000): Phenolic compounds and antioxidant properties in the snow alga Chamydomonas nivalis after expose to light, J. Appl. Phycol. 11: 559-566, Fábregas J., Otero A., Mased A. & Dominguez A. (2001): Two-stage cultures for the production of astxanthin from Haemotococcus pluvalis, J. Biotechnol. 89: 65-71.
Thus, US 2004/225167A1 describes a method for the production of carotenoids, zeaxanthin from green chlorphyta algae, it more particularly describing a method by which a carotenoid in a detergent-insoluble agent is produced. WO 2008/141757 or EP 995 325 A1 likewise describe a method for producing astaxanthin from Haematococcus pluvialis with which the carotenoid can be made in large quantities. To date no industrial application of the constituents of snow algae is known.
Continually cultivating snow algae, upgrading the biomass and isolating the cellular components still present a particular major challenge. Cultivating snow algae and isolating individual secondary metabolites are described, for example, in KR 20000072316 A or JP 0908772. Whilst US 2008/254056 A1 describes cultivating green algae of the species Haematococcus pluvialis and isolating astaxanthin. Here again, application of the extracts is restricted to the isolated substances such as astaxanthin or lutein.
In addition to the above, substances extracted or isolated from organisms exposed to extreme UV stress or water stress (dryness; freezing) likewise already find application as active ingredients in anti-aging cosmetics, examples of such active ingredients being ectoin and extracts with mycosporine-like amino acids (MAA). Ectoin is a low-molecular protecting agent belonging to the group of osmolytes or compatible solutes, it being produced by halophilic bacteria that live in salt flats. Ectoin protects the cells from heat and drought. DE 199 11 775 A1 describes the use of ectoin in cosmetic formulations for main cell DNA guarding against UV radiation and other DNA-detrimental factors, whilst DE 100 55 558 A1 describes skin care cosmetic preparations containing an extract of the green alga Prasiola crispa antarctica at home in the Antarctic and which produces UV-absorbing substances (mycosporine-like amino acids).